Deciduous Teeth

Question 1

Clinical difference between primary and permanent teeth?

Answer 1

• Colour: primary is much whiter
• Permanent teeth are much bigger
• Wider and deep contact points between primary molars: primary more of a face if contact but with permanent is to a point
• Pulp horns in primary are larger than permanent teeth
• Cervical ridge present on all primary teeth and permanent molars

Question 2

Deciduous teeth - #? names?

Answer 2

#:
- 20 in total
Names:
- central and lateral incisors
- canines
- molars

Question 3

Primary chronology of development - Incisors? Canines? First/Second molar?

Answer 3

Incisors:
- calcify (13-16 weeks)
- crown comp (1.5-3 months)
- eruption (6-9 months)
Canines:
- calcify (15-18 weeks)
- crown comp (9 month)
- eruption (19-20 month)
First molar:
- calcify (14-17 weeks)
- crown comp (6 month)
- eruption (12-15 month)
Second molar:
- calcify (16-23 week)
- crown comp (10-11 month)
- eruption (24-36 month)

Question 4

Primary eruption dates for Max (A-E) and Mand (A-E)?

Answer 4

Max: months
A - 8-12
B - 9-13
C - 16-22
D - 13-19
E - 25-33
Mand: months
A - 6-10
B - 10-16
C - 17-23
D - 14-18
E - 23-31

Question 5

Primary maxillary central incisor - defining features?

Answer 5

Labially:
- mesio-distal diameter of crown greater than permanent in relation to crown length
- mesial incisal angle sharper than distal angle (rounded)
Palatal:
- well developed marginal ridges and cingulum
Incisal:
- incisal edge centered over bulk of crown and straight
- labial surface broader and smoother than palatal
- palatal surface tapers to cingulum
- mesial and distal aspect are broad
Root:
- single, ovoid Xsec
- one canal 2 pulp (mesial and distal)
- root points labially

Question 6

Primary maxillary lateral incisor - defining features?

Answer 6

Labially:
- smaller dimensions (like central)
- crown length greater than width
- disto-incisal angle more rounded than central
Palatally:
- root is longer in proportion to crown length than central

Question 7

Primary mandibular central incisor - defining features?

Answer 7

Labially:
- flat crown no developmental lines
- crown tapers evenly from mesial to distal contact areas
Lingual:
- marginal ridges and cingulum well formed
- surface may be flat level with marginal ridges
Incisally:
- ridge straight and bisects crown
- outline of crown emphasises the crest of the contour at the cervical third labially and lingually
- crown tapers to cingulum
Root:
- single tapered root, tends to curve distally and not flat as permanent incisor
- 1 canal with mesial and distal pulp horn

Question 8

Primary mandibular lateral incisor - defining features?

Answer 8

Labially:
- fundamental outlines similar to primary central incisor
- lateral is larger in all measurements except labio-lingually
Lingually:
- cingulum and fossa more pronounced than central
-incisal edge may slope downwards distally and make contact with canine

Question 9

Primary maxillary canine - defining features?

Answer 9

Labilally:
- longer and sharper than permanent
- crown symmetrical
- mesial slope longer than distal slope
Lingually:
- well developed cingulum
- lingual ridge divides lingual fossa into shallow mesial and distal fossae
Root:
- single
- one canal with mesial and distal pulp horn

Question 10

Primary mandibular canine - defining features?

Answer 10

Labially:
- little difference from maxillary
- distal ridge longer than mesial
Lingually:
- poorly defined enamel ridge
- cervical undulation greater on mesial surface
Root:
- single, triangular xsec
- curves distally and labially
- one root but no pulp horns

Question 11

Primary maxillary first molar - defining features?

Answer 11

Root:
- 3 (palatal, mesio/distobuccal), more divergent
Buccally:
- 2 cusps; large mesiobuccal and diminutive distobuccal
Lingually:
- 2 cusps: large mesiopalatal and small distopalatal
Mesial/distally:
- wider mesial than distal
- distobuccal cusp long and sharp
- tubercle of Zuckerkandl (large bulge of enamel in cervical region of mesiobuccal root)
Occlusally:
- central fossa
- mesial.distal triangular fossa
- central groove
- defined buccal developmental groove
- supplemental grooves

Question 12

Primary maxillary second molar - defining features?

Answer 12

Root:
- 3 divergent roots (palatal, mesio/distobuccal)
- 3 root canals (mesio/distolingual and distobuccal)
Buccally:
- tooth replica of maxillary first permanent molar
Occlusally:
- 4 cusps (mesio/distolingual and mesio/distobuccal)
- cusp of Carabelli present lingual surface of mesiolingual cusp

Question 13

Primary mandibular first molar - defining features?

Answer 13

Root:
- 2 divergent roots (mesial/distal)
- both flattened mesiodistally
- 2 root canals and 3 pulp horns (lingual, mesio/distobuccal)
Buccally:
- 2 cusps; mesio/distobuccal
- from mesial or distal aspect the buccal cusps lean lingualls
Lingually:
- 2 cusps; large mesiolingual and small distolingual
Occlusally:
- mesiolingual cusp largest and most developed
- buccal developmental groove divides the 2 buccal cusps evenly

Question 14

Primary mandibular second molar - defining features?

Answer 14

Tooth similar to perm mandibular first molar
5 cusp tooth
Root:
- two divergent roots flattened mesiodistally
- 2 root canals and one pulp horn per cusp
Buccally:
- 3 cusps (mesio/centro/distobuccal)
Lingually:
- 2 cusps (large); mesio/distolingual
Occlusally:
- central pit